Production of shaped objects from viscose



United States PatentfQ PRODUCTION OF SHAPED OBJECTS FROM vlscosn Kurt Heuer, Oberbruch-Grebben, Bez. Aachen, Hugo Elling, Grebben, Bez. Aachen, and Richard Elssner, 'Randerath, Bez. Aachen, Germany, assignors to American Enka Corporation, Erika, :N.'C., a corporation of Delaware This invention relates to a process for the production from viscose of artificial threads and other shaped objects, including .films, having greatly improved properties as regards their resilience-and their smaller degree of swelling. The invention also relates to the resulting products.

One of the principal objects of the present invention is to provide a new and improved method "for'spinning artificial products such as threads and other shaped objects from viscose in such manner as to confer upon them greatly improved properties as regards their strength, elasticity and abrasion-resistance. \A further object of the invention is to provide a new and improved method for producing products of th'ekind just indicated having unusually strong and well-defined peripheral zones. A still further object of the invention is to provide improved products of the kind indicated.

The manner in which these and other objects and features of the invention are attained will appear more fully from the following description thereof, in which reference is made to typical and preferred procedures in order to indicatemore fully the nature of the invention, but without intending to limit the invention thereby.

Very great value has been attached for a number of years in the viscose artificial fiber industry to .the pro- 'duction of threads having a strong-and well-definedflperipheral zonev because of their better properties as ,regards resilience vancl their smaller degree of swelling. For the production of such fibers, use has been mad'e'of unripened viscoses and spinning baths which contain .zinc sulphate having comparatively low acid contents. The zinc sulphate content has in fact been considered to be an essential condition for the production of these fibers.

Processes are also known by which :such th readsmay he obtained bysupplying additives to the viscose onto the spinning bath. Such additives are alkali-soluble monoamines, which must also be soluble in the :spinning baths which are used and which contain 325% of zinc sulphate; In accordance with the prior known processes, :the additions of such amines should not'amount to more than 4 millimols/ 100 g. of viscose.

When using such prior processes, difliculties were encountered from the fact that only very small fluctuations are permissible both as regards the amounts of amines added to the viscose and as regards the concentrations of acid and zinc sulphate to be maintained in the spinning bath if the expected technical eifect is to be produced.

According to the present invention, it has now been discovered that threads having improved strength and elasticity values may be obtained if, in contrast to the hitherto known processes, complex compounds are added to the viscose having the following formula:

[Me(X) lAn ICC 2 in which Me represents iron, zinc, chromium, cadmium, tin; X represents alkyl amine, alkanol amine or aryl amine; and An represents chloride, sulphate or nitrate.

The process may be carried out in a particularly advantageous manner by using Zn S04 These compounds are added just prior to the spinning operation in amounts of 0.06-0.4% by weight, and preferably 0.12% by weight. Viscoses having a conventional composition of 7 to 8% of cellulose and 5 to 7% of NaOH, with a gamma value of at least 42, are spun at temperatures of 45-70 C. in spinning baths having the following composition: 40-65 g/l. of H 50 .160- 260 g./l. of Na SO and 30-50 g./l. of ZnSO It is expedient to operate with thread withdrawal speeds of 40-60 m./rnin. The Withdrawal speed may be increased, however, if care is taken With'theaid of known means to impart to the spinning bath, at least in the first section of its travel "after the spinning nozzle, a velocity which is substantially equal to the thread velocity so that the friction between the thread and the spinning bath is thereby substantially reduced. The length of travel in the bath is tobe'at least 30 cm. In a second bath, which contains approximately 2-10 g./l. of H SO the thread is subjected to a drawing of SO-120%, preferably '95-l00%, at temperatures higher than 90 'C. The thread may then be deposited onto a bobbin, into a centrifuge or onto a perforated Web, as desired.

"The threads spun by the process accordingto the present invention have strength values of 380-400 g./'100 den., which may be increased by subsequent drawing to 420-440 g./100 den. The finally drawn threads show a very high degree of shrinkage, namely of more than 8% and have a low degree of swelling.

In order to indicate still more fully the nature of the present invention, the following examples of typical procedure :are set forth, it being understood that this description is presented by way of illustration only, and not as limiting the seope'of the invention.

Example 1 Alkali cellulose consisting of linters or wood cellulose is sulphidized for 5 hours with 42% of CS and the xanthate obtained is dissolved to form a viscose with 7.3% of cellulose and 5.5% of NaOH. The viscose is de-aerated, filtered and finally ripened in the usual manner and is mixed 5 hours before being spun with 0.1% by weight of a compound having the formula The viscose is spun with a gamma value of 45 from a spinneret with 1000 orifices to provide a thread of 1650 den., this taking place in a bath with 49 g./1. of H 200 g./l. of Na SO and 39 g./l. of ZnSO The thread then travels through a distance of 70 cm. in the spinning bath and is withdrawn by a first roller at 23 m./min. The thread then travels through a second bath with 6 g./l. H 80 at a temperature of C. and is withdrawn by a second roller at 46 rn./min.; that is to say,v it is stretched by The thread travels from the second roller onto a bobbin and is collected thereon.

the thread is then rewound, washed, finished and dried. It has the following textile data:

is added to a viscose with 7.3% of cellulose and 5.5% of NaOH about 10 minutes before spinning, whereupon it is spun in a bath containing 55 g./l of H 80 17 g./l. of Na SO and 45 g./l. of ZnSO the withdrawal conditions and the stretching being the same as in Example 1. The Washed and finished threads are subjected to a final stretching by 8% and are thereafter dried. They have the following textile data:

Strength, gJden. Elongation, percent dry Wet dry wet Example 3 0.1% by weight of 7 [Fe( (CH CH(OH) CH NI-I) lCl is added to a viscose with 7.3% of cellulose and 6% of NaOH about 1 hour before spinning. It is then spun in a spinning bath which contains 60 g./l. of H SO 220 g./l. of Na SO and 50 g./l. of ZnSO The bath has a length of 70 cm. It is operated with a thread withdrawal velocity of 23 m./min. and the thread is stretched by 100% by being withdrawn at a velocity of 46 m./min. in a second dilute acid bath at a temperature of 90 C. From the second roller, the thread runs into a centrifuge operating at 6,000 r.p.m. and is given a twist of 120 turns per meter. The thread is then washed and finished and dried after final stretching of 8%. In this way, there are obtained threads with the following textile data:

Strength Elongation gJden. percent dry wet dry wet While specific examples of preferred methods and products embodying the present invention have been described above, it will be apparent that many changes and modifications may be made in the methods of procedure and the products without departing from the spirit of the invention. It will therefore be understood that the examples cited and the methods and procedures set forth above are intended to be illustrative only and are not intended to limit the invention.

What is claimed is:

1. A process for the production of regenerated cellulose threads from viscose, comprising incorporating into viscose 0.060.4% by weight based on the viscose of a complex compound having the formula:

[Me(X) lAn wherein Me is selected from the class consisting of Fe, Zn, Cr, Cd, and Sn; X is selected from the class consisting of alkyl amine, alkanol amine, and aryl amine; and An is selected from the class consisting of Cl, S0 and N0 extruding the viscose containing said complex compound into an aqueous bath having approximately the composition 40-65 g./l. of H 50 and 30-50 g./l. of ZnSO and treating the resulting extruded object in a second hot bath containing approximately 2-10 g./l. of H and stretching same by a factor of approximately 8'Ol20%.

2. A process according to claim 1, wherein the complex compound has the formula:

3. A process according to claim 1 wherein the plex compound has the formula:

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1. A PROCESS FOR THE PRODUCTION OF REGENERATED CELLULOSE THREADS FROM VISCOSE, COMPRISING INCORPORATING INTO VISCOSE 0.06-0.4% BY WEIGHT BASED ON THE VISCOSE OF A COMPLEX COMPOUND HAVING THE FORMULA: 